Car-axle lighting system.



J. L. WOODBRIDGE. CAR AXLE LIGHTING SYSTEM.

APPLICATION FILED JUNE 30.1918

Patented Mar. 2, 1915.

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JOSEPH LESTER WOO'DBBIDGE, DIE-PHILADELPHIA, PENNSYLVANIA.

CAR-AXLE LIGHTING sYsrnM.

Specification of Letters Patent.

Originalupplicetlon flied January 10, was, Serial No. 410,259. Divided and this pplication filed June so.

191s. SerialNo. 776,551.

To all whom it may concern ,Be it known that I, Josnrrr Lns'rnu Wood BIuDGE, a' citizen of the. United States, and residentof Philadel his, in the county of Philadelphia and tute of Pennsylvania,

have invented certain-new a'ndnse'ful lin i provements in Cor-Axle Lighting Systems,

of which the following is u specification.

My invention relates to systems in which it generator driven at variable speed i's used for supplying current to a constaht'poten tial circuit, as in the case of a generator for train lighting driven'fron'i the axle of the or a generator driven by a windmill at variable speed.

The principal object of my invention is to provide simple and reliable means for maintaining a constant potential at the generator terminals With Widely varying speed changes.

Other objects as well as the general nature of my invention will be more "learly seen from the following description taken in corn nection with the accompanying drawing which is a diagrammatic View of an an, lighting, system embodying features of the invention.-

In the drawing, G is. a direct current generator supplying current to the translating deviccn l1 and driven at a variable speed by means of a belt M running on a pulley mounted on the cur axle. ()n the some shaft us the generator armature, is mounted on exciter E. This exciter consists of a frame or core of magnetic material 8, on which is :1 Winding 9, connected to it commutator 10, in the usual manner. To avoid confusion,

only it few of the connections from the winding to the commutator are shown. Two pairs of brushes 4-5 and 6-7 bear upon. this cominutz'itor at points displaced at an angle of 90. One pair of brushes 5 is mmnected to a source of constant potential, here shown as it storage battery B. The other pair 6 7. is connected to the field windings S? and of the generator G. The operation of'this apparatus is then us follows: Assume first that the generator (l and the exritrr l), are driven at 11 certain fixed speed: the battcry will tendto send current through the armature windingl) between the 'uuslles 45. This current would luu'iunu't eXc 'ssive were it not for the counter clmrtru-nmtivc-force developed in this iii-111:1 turn by rcuson of its rotation in the held profthc generator; fluduced by the current output from the brushes 6 7, as explained below. Assume at small amount of current flowing in the armature winding 9 between the brushes l-5. This current will produce a field whose ux'isqvill be in line with the brushes This field will produce an electro niotive' force' across the brushes 6-7 and this .clectro "motive force will send current through thelfieldjwindings St. and S of I The effect of this latter current. however. on the exciter E will be to produce a second field Whose axis will he in line with the brushes 6-7, and this second field will produce a counter-electroinotive-force between the brushes zl-5 sufficient to prevent any further flow of current from the batteryr-- It will be seen that for any given speed the flow of current from the brushes 6 7 through the field windings S and will depend upon the voltage of the battery B, and will be sufficient to pro- .luce the field'necess'ary to develop the counter-electro-motive-force required to balance that of the battery. If, however, the speed should increase a weaker field, and, therefore, a smaller amount of-current from the brushes 6--7 will be required to produce the some counter-electromotive-force. It will be seen, therefore, thatns the speed of the generator and exclter varles, the current in Patented Mar. 2', 1915.

the field windings S and S will vary in the opposite direction, thus maintaining constunt voltage on the genrutor G, regardless of changes of speed. It will also be noted that ii the direction of rotation reverses, the current in the field windings S and S will also reverse, so that the generator will maintain the some polarity.

This application is a. division of my applicution, Serial No. 410,259, filed January 10th, 1908.

W'hnt I claim and desire to secure by Letters Patent is:

1. A dynamo and its cxciter mechanically connected, it source of constant potential iudc endent of the dynamo. and two sets oi oi trically displaced brushes for the exciter, whereof one set is connected to the source of constant potential and whereof the other is connected to the field windings of the dynamo.

2. A dynamo und its cxcitcr mccluuiicully connected, a. source of potential. independent displaced brushes for the exciter, whereof one set is connected to the source of potential and whereof the other is connected to the field windings of.the dynamo.

3. A dynamo, a variable speed driving source for said dynamo, an eiiciter, means for driving the exciter at a speed proportional to that of the dynamo, a source of constant potential independent of the dynamo, and two sets of electrically displaced brushes for the exciter, whereof one 'set-. is connected to the source of constant potential and whereof the other is connected to the field windings of the dynamo.

4. A dynamo, a variable speed driving source for said dynamo, an-exciter, means for driving the exciter at a" speed proportional to that of the dynamo, a source of potential independent of the dynamo, and two sets of electrically displaced brushes for the exciter, whereof one set is connected to the source of potential and whereof the other is connected to the field windings of the dynamo.

5. In combination a commutator, two sets of brushes bearing upon said commutator, independent electrical circuits connecting the opposite brushes of each set, means including. a n'iagnetic circuit and windings connected to the commutator for producing between the opposite brushes of each set an electro-motive-force and whereof the 't electro-1notive-1Eorce determined by the current in the. circuit connectmgthe other set,

.a'dynamo having field windings connected in series with one of said circuits a source of electroanotiveforce independent of said dynamo included in the other circuit, and means for producing relative rotation of brushesand commutator proportional. to'the speed of the dynamo.

6. In combination, a dynamo having appropriate field windings, a magnetic circuit all parts of which are relatively fixed, a. winding in inductive relation to the magnetic circuit, a commutator for said wind: ing, a source of. direct current electro-niotive force independent of the dynamo, two se"s of electrically displaced brushes bearing upon said commutator, whereof one set is connected to the source of: direct current is connected to the field windings .e dynamd, and means for prdur' rotation of brushes and commutator proper tional to the speed of the dynamo.

In. testimony whereof I. have hereunto signed my'name. v

iosrra LESTER Wootrrnbea Witnesses:

J. H. TRACY, H. A. Tnonannu,

g reiative; 

